National Instruments 653X User Manual
Page 133
Glossary
© National Instruments Corporation
G-7
pretrigger
acquiring data that occurs before a trigger
propagation delay
the amount of time required for a signal to pass through a circuit
protocol
the exact sequence of bits, characters and control codes used to transfer data
between computers and peripherals through a communications channel,
such as the GPIB
PXI
PCI eXtensions for Instrumentation—a rugged, open system for modular
instrumentation based on CompactPCI, with special mechanical, electrical,
and software features
R
real time
a property of an event or system in which data is processed as it is acquired
instead of being accumulated and processed at a later time
REQ
Request—Handshaking signal generated by the peripheral device,
indicating it is ready. In some transfer modes, the 653X device can
internally generate a REQ signal. The REQ signal with a bar above the
name indicates it is an inverted request signal.
RGND
reserved ground
RT Series DAQ Device
A collection of one, two, or four ports and an associated timing controller.
All handshaking I/O, pattern I/O and buffered operations must be
performed on groups.
RTSI bus
Real-Time System Integration Bus—the National Instruments timing bus
that connects DAQ devices directly, by means of connectors on top of the
devices, for precise synchronization of functions
S
s
seconds
S
samples
S/s
Samples per second—used to express the rate at which a DAQ device
samples an analog signal
sample
an instantaneous measurement of a signal, normally using an
analog-to-digital convertor in a DAQ device